Random early detection gateways for congestion avoidance
TL;DR: Red gateways are designed to accompany a transport-layer congestion control protocol such as TCP and have no bias against bursty traffic and avoids the global synchronization of many connections decreasing their window at the same time.
Abstract: The authors present random early detection (RED) gateways for congestion avoidance in packet-switched networks. The gateway detects incipient congestion by computing the average queue size. The gateway could notify connections of congestion either by dropping packets arriving at the gateway or by setting a bit in packet headers. When the average queue size exceeds a present threshold, the gateway drops or marks each arriving packet with a certain probability, where the exact probability is a function of the average queue size. RED gateways keep the average queue size low while allowing occasional bursts of packets in the queue. During congestion, the probability that the gateway notifies a particular connection to reduce its window is roughly proportional to that connection's share of the bandwidth through the gateway. RED gateways are designed to accompany a transport-layer congestion control protocol such as TCP. The RED gateway has no bias against bursty traffic and avoids the global synchronization of many connections decreasing their window at the same time. Simulations of a TCP/IP network are used to illustrate the performance of RED gateways. >
Cites background from "Random early detection gateways for..."
...Many researchers have observed that, when using TCP, connections with a long round-trip time that go through many bottlenecks have a smaller transmission rate that the other connections [10, 12, 20]....
"Random early detection gateways for..." refers background in this paper
...In addition, the emphasis on avoiding the global synchronization that results from many connections reducing their windows at the same time is particularly relevant in a network with 4.3-Tahoe BSD TCP [ 14 ], where each connection goes through Slow-Start, reducing the window to one, in response to a dropped packet....
...In addition to the design goals discussed in Section3, several general goals have been outlined for congestion avoidance schemes [ 14 , 16]....
...1Jacobson [ 14 ] proposed gateways to monitor the average queue size to detect incipient congestion, and to randomly drop...
...As long as wq is chosen as a (negative) power of two, this can be implemented with one shift and two additions (given scaled versions of the parameters) [ 14 ]....
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